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Letters to the Editor October 2013

Migraine is a marker for systemic disease Dear Editor, We read with interest the article titled “Retinal arterial occlusions in the young: Systemic[1] associations in Indian population by Ratra et al. Authors have mentioned severe headache, floaters and transient blurring of vision as the presenting symptoms in a subset of patients. Visual aura  (migraine) are fully reversible symptoms including positive features (e.g., flickering of lights, spots or lines) and negative features  (i.e.,  loss of vision). A  migraine diathesis may be a marker for an underlying defect such as hypertension, hypercoagulability, lupus erythematosis or mitral valve prolapse and therefore might occasionally co‑occur with[2] vascular occlusion or retinal vasospasm. Experts disagree whether retinal migraine is a rare or common cause of monocular visual loss and whether the mechanism is spreading depression or vasospasm. Complicated migraine refers to a permanent neurologic deficit whether it is visual, motor or sensory in origin. In some instances the stroke does not respect the usual middle or posterior cerebral artery territories suggesting that a strict vascular mechanism is insufficient to[3] explain all migraine‑related stroke phenomena. Cocaine abuse cause hypertensive surges, stroke, arterial and venous thrombosis. Neuroimaging studies in cocaine abusers demonstrated abnormal perfusion involving the infraparietal,[4] temporal and anterofrontal cortex and basal ganglia. Dopamine‑rich brain regions appear to be relatively specific targets for cocaine‑induced cerebral ischemia. Dopamine is one of the[5] numerous neurotransmitters present in outer and inner layers of the retina. Cocaine abuse,[3] exercise and lupus cause non‑migrainous retinal vasospasm and transient monocular visual loss. Authors have documented hypertension, cerebrovascular accident and basal ganglia infarction in a 37‑year‑old patient. In our practice we routinely inform the possibility of underlying systemic disease and importance of physician consultation in all patients with migraine. Perimetry may be useful to identify coexisting cerebral ischemia in patients with retinal vascular occlusion and normal neuroimaging study. We appreciate the authors’ effort and research work.

Acknowledgment We acknowledge the support provided by Dr. Kummararaj, Director, AG Eye Hospital for this article.

Natarajapillai Venugopal, M R Sriram Gopal1 1

Neuroophthalmology Clinic, AG Eye Hospital, Athreya Retinal Centre, Trichy, Tamil Nadu, India

Correspondence to: Dr. N. Venugopal, Flat No: 19, Mathuram Apartment, Officer’s Colony, Behind YMCA, Puthur, Trichy, Tamil Nadu, India. E‑mail: [email protected]

References 1. Ratra  D, Dhupper  M. Retinal arterial occlusions in the young: Systemic associations in Indian population. Indian J Ophthalmol 2012;60:95‑100. 2. Jacqueline M, Winterkorn S. “Retinal migraine” is an oxymoron. J Neuroophthalmol 2007;27:1‑2. 3. Liu GT, Volpe NJ, Galetta SL. Neuro – ophthalmology, diagnosis and management. 2nd ed. New York: Saunders Elsevier; 2010. 4. Johnson BA, Devous MD, Ruiz P, Daoud NA. Treatment advances for cocaine‑induced ischemic stroke: Focus on Dihydropyridine‑class calcium channel Antagonists. Am J Psychiatry 2001;158:1191‑8. 5. Zrenner  E, Hart  N. Drug‑induced and toxic disorders in neuro‑ophthalmology. In: Schiefer U, Wilhelm H, Hert W, editors. Clinical neuro ophthalmology, A practical guide. Berlin: Springer; 2007. p. 223‑32. Access this article online Quick Response Code:

Website: www.ijo.in DOI: 10.4103/0301-4738.121094 PMID: ***

Comment on “Effect of dacryocystorhinostomy on systemic adverse effects of topical timolol maleate” Dear Editor, I commend the authors of the study “Effect of dacryocystorhinostomy on systemic adverse effects of topical timolol maleate” for a well conducted study.[1] However I wish to point out some of the confounding variables in the study which affect the conclusion. The age, sex and body weight of the sample under study is not mentioned. The bioavailability of any drug will be affected by the age, sex and body weight of the individual.[2] The results would have been more reliable if the study was done on a sample of similar age group, sex and body weight. The patients were not fasting before the test and not kept fasting for two hours thereafter. The presence of food in the stomach will alter the pharmacodynamics of the drug even if the topical drug is not metabolized until the second pass.[2] The mean IOP in the control situation was 14.8 mm  Hg. This was recorded in the eye on the unoperated side. The mean IOP in the eye on the operated side is not mentioned and need not necessarily be the same. The comparison of the results of situation A and B are hence not valid. The repeat test after DCR surgery was conducted at 6 weeks after surgery when there is a possibility of inflammation of the nasal mucosa which may increase the absorption of the drug. The serum peak levels of Timolol after a drop of topical

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Timolol maleate is achieved 15  min after instillation of the drug at which time no record of IOP, BP or pulse was made.[3] Finally the study would have been better supported if accompanied by an assay of serum levels of Timolol maleate. In conclusion, it may be said that following DCR surgery there is a strong possibility of altered pharmacokinetics of the drug rather than the pharmacodynamics.

Cynthia Arunachalam Department of Ophthalmology, Yenepoya Medical College, Yenepoya University, Mangalore Correspondence to: Dr. Cynthia Arunachalam, Department of Ophthalmology, Yenepoya Medical College, Yenepoya University, Deralakatte, Mangalore. E-mail: [email protected]

References 1. Roy  K, Mondal  KK, Ray  B, Chakraborty  S, Biswas  S, Baral  BK. Effect of dacryocystorhinostomy on systemic adverse effects of topical timolol maleate. Indian J Ophthalmol 2012;60:105‑7. 2. Fraunfelder  FT. Ocular drug delivery and toxicology. In: Fraunfelder  FT, FraunfelderFW, Chambers  SW. editors. Clinical Ocular toxicology. 1st ed. Philadelphia: Saunders Elsevier; 2008. p. 9. 3. Ohno Y, Iga T, Yamada Y, Nagahara M, Araie M, Takayanagj R. Pharmacokinetic and pharmacodynamic analysis of systemic effect of topically applied timolol maleate ophthalmic gelling vehicle (Rysmon® TG). Curr Eye Res 2005;30:319‑28. Access this article online Quick Response Code:

Website: www.ijo.in DOI: 10.4103/0301-4738.121095 PMID: ***

Completion rates of anterior and posterior continuous curvilinear capsulorrhexis in pediatric cataract surgery for surgery performed by trainee surgeons with the use of a low‑cost viscoelastic Dear Editor, We would like to congratulate Dr.  Muralidhar and his colleagues for the study on a subject which is an established clinical practice at least in developing countries, but has never been well documented. Results of this study are of great value for ophthalmologists in developing countries like India where care and cost of care has to be finely balanced. In their non‑randomized observational study, Muralidhar et al., found that the completion rate of anteriorcontinuouscurvilinear capsulorrhexis by trainee surgeons with the use of 2%

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hydroxypropylmethycellulose was 66.7% and overall completion rate with the help of a senior surgeon was 81.8%.[1] This is acceptable as compared to 90% completion rate with use of Healon in studies by Jeng et al.[2] Again, Hamada et al., reported a completion rate of anterior and posterior capsulorrhexis of 100% with use of Healon GV.[3] The completion rates of posterior capsulorrhexis reported by the authors in their study was 90%, which is fairly comparable. We feel that the authors have not factored in two variables which may change the outcomes in a similar study. These two factors are the age of the patient and the experience of the surgeon. Majority of the patients in their study group are 2 years or older except one patient. Only 1 child who is under 2 years had an extension of the anterior rhexis.Cataract surgery in younger children often is more challenging in view of higher positive vitreous pressure and shallower anterior chambers.[4] With the publication of Infant Aphakia Treatment Study results, more children younger than two years are likely to undergo primary intraocular lens (IOL) implantation.[5] We genuinely feel that this study could have been more valuable and complete had the authors included more children less than 2 years of age. We also feel that completion rates will be lower in younger children with use of low cost viscoelastics. We agree with the authors in their conclusion, that the completion rates are expected to be better for experienced surgeons. It would have been helpful if they had compared completion rates of experienced surgeon to that of trainees in age matched controls. In addition, the authors have not included cataracts with anterior segment anomalies like zonular weakness, fibrotic capsules, capsular plaques, persistent hyperplastic primary vitreous etc., in their study. Further studies are needed to assess completion rates with low cost viscoelastic in these admittedly difficult cases.

Sumita Agarkar, Chongtham S Devi Department of Pediatric Ophthalmology, Sankara Nethralaya, College Road, Chennai, India Correspondence to: Dr Chongtham Sarda Devi, Department of Pediatric Ophthalmology, Sankara Nethralaya, 18, College Road. Chennai - 600006, India. E-mail: [email protected]

References 1. Muralidhar  R, Siddalinga Swamy  GS, Vijayalakshmi  P. Completion rates of anterior and posterior continuous curvilinear capsulorrhexis in pediatric cataract surgery for surgery performed by trainee surgeons with the use of a low cost viscoelastic. Indian J Ophthalmol 2012;60:144‑6. 2. Jeng BH, Hoyt CS, McLeod SD. Completion rate of CCC in pediatric surgery using different viscoelastic materials. J Cataract Refract Surg 2004;30:85‑8. 3. Hamada S, Low S, Walters BC, Nischal KK. Five year experience of the TIPP technique for anterior and posterior rhexis in pediatric cataract surgery. Ophthalmology 2006;113:1309‑14. 4. Wilson  ME, Pandey  SK, Werner  L. Pediatric Cataract Surgery: Current Techniques, Complications and Management. In: Agarwal S,

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